Broken Base: On one side, people praise it for bringing back memories of Mister Rogers', or just praise it as a standalone series. On the other side, people pan the Adobe Flash (and the computer generated animation, if they've actually seen an episode) and the series for being too cartoonish and not staying true to Rogers.
Ear Worm: No surprise, as the songs are intentionally designed with a small hook that is sung throughout the story before the full song is heard later. Besides the theme songs, those that have watched regularly or listened to the music albums will likely be instantly familiar with the following, to name a few:
If you have to go to the potty, stop and go right away! Flush and wash and be on your way!
It's almost time to stop, so choose one more thing to do / I'll take another twirl and then I'll come away with you...
You can take a turn, and then I'll get it back!
When you feel so mad that you wanna roar / Take a deep breath, and count to four!
The show also has a rivalry with fans of just about every PBS Kids show currently running, due to Daniel's Adored by the Network status making fans of the other shows (especially fans of Ready Jet Go!, Wild Kratts, Nature Cat, and Odd Squad, since those 4 are the most popular PBS Kids shows on air that aren't Long-Runners like Sesame Street, Cyberchase, and Arthur) feel like PBS is marginalizing the other shows in order to make Daniel seem more important. For example, PBS Kids released the DVD for the TV movie Tiger Family Trip right off the bat, but refused to release DVDs for the TV movies that premiered over the summer of 2017 (Nature Cat: Ocean Commotion, Wild Kratts Alaska: Hero's Journey, and Ready Jet Go! Back to Bortron 7.)
It's quite possible to find a lot of bronies that hate this show, as they believe that only My Little Pony is teaching good morals about friendship and consider this show to be inferior.
Heartwarming in Hindsight: In one week of "Mr. Rogers" episodes, Prince Tuesday is left in the care of babysitters, and has to be helped through it. Now, he's been able to pay it forward.
Less Disturbing in Context: Dad Tiger "what happened? You both look sticky and wet" during "Daniel Loves Tigey". Says this to Daniel as Margaret walks up behind him. They were playing together. It becomes clear with preceding/following comments that "you both" refers to Daniel and Tigey and that Margaret spilled orange juice on them.
Narm: In 'Daniel Uses His Words", Miss Elaina tosses Daniel's toy Tigey, and just the way that he was being thrown, Tigey was being tossed in SLOW MOTION and with the dramatic music along with it, not so fitting to the moment. There's just something dang funny about it.
"Mad at the Beach" has Daniel scowling at the camera, red-faced and all, and still using his angry voice when he asks us how we'd feel if a wave knocked over our sandcastle.
Periphery Demographic: It's becoming fairly obvious that the show has a growing periphery demographic consisting of those who remember the original Mister Rogers fondly and enjoy seeing the characters again in this new show, parents who have watched the show with their children and found it charming, and adult fans who either didn't really know the original Mister Rogers show or were only passingly familiar with it, but like the new show. Those who liked Blue's Clues and are aware that the show is being made by the company formed by its creators (and others that are aware it's also made by the folks that brought us Super Why!) may be part of the general mix as well.
Some Anvils Need to Be Dropped: The episodes on voting remind us that we should try to find something good about alternatives when we don't get what we want. It's important for everybody.
They Changed It, Now It Sucks: Those who remember Mister Rogers and don't like this show generally believe this. Reasons range from "children need to see real people instead of cartoons" and "it's missing that warmth and magic" to "it's too cartoonish and hyper" and "this is blasphemy! Mister Rogers must be rolling in his grave!"
Unfortunate Implications: In the end sequence of every episode when the children board trolley, the cats Daniel & Katerina (predator species) sit in front with the white male ruler (Prince Wednesday) while the bird (O) and black female subject (Miss Elaina) sit in the back of the bus.